Biotransformation...
Need I say more? Let's dive in.
Hops, fruits, and flowers can produce biotransformation, a transformation of flavor and aroma without synthetic chemicals.
Glycosides are non-volatile, odorless hop compounds that can be hydrolyzed to produce sugars and alcohols when in contact with acid or enzymatic activity. These glycosides, when transformed, will produce simple alcohols, terpene alcohols, and carbonyl compounds. To transform these glycosides via beta-glucosidase, a yeast strain proven to do the job must be used. Wine strains like AR2000 and Rapidase Revelation Aroma used at 0.5 grams per 5 gallon batch are recommended by Janish.
Rather than using a wine yeast, you can use a wine enzyme extract in conjunction with your standard Hazy IPA strain. Isolated enzymes can be poor attenuators, but if used with another yeast, they can drop gravity and pH faster, accentuate the aroma profiles, and soften perceived bitterness.
Yeast blending was something that never occurred to me until reading this section. Particularly in a Hazy IPA, utilizing a wine enzyme or yeast may be nice with hops from New Zealand or Australia that feature tons of bright fruits and white grape characteristics. Furthermore, I wonder what the extent of yeast blending is. Perhaps a champagne yeast/enzyme would efficiently dry out a lager, enabling the brewer to skip decoction and still achieve complex profiles? A few of Vintner's Harvest strains look suitable.
The presence of sugar decreases biotransformation likelihood. So it seems best to introduce enzymes or yeast additions at the end of primary fermentation, after the sugars have been chewed up. Lower temperatures also decrease biotransformation likelihood ... but not even room temperature is ideal; more like around 100 degrees! F that.
Lalvin T73 wine yeast is shown to be a durable workhorse that can release additional flavors via its exo-beta-glucanase enzyme. If you find an ale strain that also produces exo-beta-glucanase, the same unlocking of flavors will occur.
Terpenoid alcohols, mentioned above, can be transformed during primary fermentation. For example, geraniol can be transformed into citronellol (sweet, rose-like) and linalool can transform into terpineol (lilac). If you wish to increase citronellol or beta-citronellol (lemon-lime) concentration, toss geraniol-rich hops into the whirlpool or at the beginning of fermentation. Centennial, Brewers Gold, Simcoe, Chinook, Mosaic, Cluster, and Ahtanum are prime candidates.
Free geraniol hops, according to a 2017 study, include Mosaic, Motueka, Cascade, Chinook, Sorachi Ace, Citra, and Bravo. Again, these have massive bioflavoring potential if used toward the start of fermentation.
If you're using a biotransforming enzyme or a wine strain, perhaps try Amarillo, Bravo, Chinook, or Mosaic, because they offer bound geraniol potential.
Coriander seeds are high in linalool. These then get transformed into citronellol, explaining why Allagash White has such a strong zesty-citrus character.
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